Remote Connection Protocols ============================== These protocols play key roles in network communication by establishing sessions and enabling secure or remote access to devices and systems. .. toctree:: :maxdepth: 1 :hidden: :includehidden: Telnet SSH RDP VNC .. list-table:: :widths: 20 60 20 :header-rows: 1 * - Protocol - Description - Use Case * - Telnet - A legacy protocol that provides remote command-line access over TCP port 23. Telnet transmits data—including usernames and passwords—in plaintext, making it vulnerable to interception. *Due to lack of encryption, Telnet is mostly replaced by SSH in secure environments.* - Remote management of legacy devices and network equipment, mainly in trusted or isolated networks. * - SSH (Secure Shell) - Provides encrypted remote shell access over TCP port 22. SSH offers strong authentication and secure data transmission, replacing Telnet for secure remote administration. - Secure remote server and network device management. * - RDP (Remote Desktop Protocol) - Microsoft protocol for remote graphical desktop access over TCP port 3389. Enables users to control Windows desktops remotely with GUI support. - Remote desktop access for Windows environments. * - VNC (Virtual Network Computing) - Platform-independent protocol for remote desktop sharing via TCP ports 5900+. Shares graphical desktop for remote control and support. - Cross-platform desktop sharing and remote technical support. .. tab-set:: .. tab-item:: Telnet **Main Features** - Provides remote command-line access over TCP port 23 - Transmits data, including usernames and passwords, in plaintext - Simple and widely supported on legacy devices - Does not provide encryption or strong authentication **RFC References** - RFC 854 – Telnet Protocol Specification - RFC 855 – Telnet Options **Use Cases** - Remote management of legacy network devices - Access in trusted or isolated network environments - Basic command-line access where security is not a concern **Alternative Protocols** - SSH – Encrypted remote shell access - Console access via serial or out-of-band management - Remote desktop protocols for GUI access (RDP, VNC) .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: What You Will Learn in This Section **Let us learn more about Telnet:** * :ref:`Learnings in this section ` * :ref:`Terminology ` * :ref:`Version Info ` * :ref:`Telnet Version&RFC Details ` * :ref:`Telnet Basic Setup on Ubuntu using IPv4 ` * :ref:`Telnet Basic Setup on Ubuntu using IPv6 ` * :ref:`Telnet Protocol Packet Details ` * :ref:`Telnet Usecases ` * :ref:`Telnet Basic Features ` * :ref:`Telnet Feature : Text based Communication ` * :ref:`Telnet Feature : Remote Login ` * :ref:`Telnet Feature : Port Based Access ` * :ref:`Telnet Feature : Network Virtual Terminal ` * :ref:`Telnet Feature : Option Negotiation ` * :ref:`Telnet Feature : Subnegotiation support ` * :ref:`Telnet Feature : Cross Platform Compatiblity ` * :ref:`Telnet Feature : Simple Protocol structure ` * :ref:`Reference links ` .. button-link:: ./Telnet.html :color: primary :shadow: :expand: Jump to "Telnet" .. tab-set:: .. tab-item:: SSH (Secure Shell) **Main Features** - Provides encrypted remote shell access over TCP port 22 - Supports strong authentication methods (password, keys) - Ensures confidentiality and integrity of data - Supports secure file transfers (SCP, SFTP) **RFC References** - RFC 4251 – SSH Protocol Architecture - RFC 4252 – Authentication Protocol - RFC 4253 – Transport Layer Protocol - RFC 4254 – Connection Protocol **Use Cases** - Secure remote server and network device administration - Automated secure scripting and file transfers - Replacing Telnet in all secure remote access scenarios **Alternative Protocols** - Telnet – Legacy, insecure alternative - RDP – Remote GUI desktop access for Windows - VPN with remote shell access for enhanced security .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: What You Will Learn in This Section **Let us learn more about SSH:** * :ref:`Learnings in this section ` * :ref:`Terminology ` * :ref:`Version Info ` * :ref:`SSH FAQs ` * :ref:`SSH Version&IEEE Details ` * :ref:`SSH Basic Setup on Ubuntu using IPv4 ` * :ref:`SSH Basic Setup on Ubuntu using IPv6 ` * :ref:`SSH Protocol Packet Details ` * :ref:`SSH Usecases ` * :ref:`SSH Basic Features ` * :ref:`Reference links ` .. button-link:: ./SSH.html :color: primary :shadow: :expand: Jump to "SSH" .. tab-set:: .. tab-item:: RDP (Remote Desktop Protocol) **Main Features** - Remote graphical desktop access over TCP port 3389 - Supports full Windows desktop GUI control - Includes features like audio redirection, clipboard sharing, multi-monitor support - Optimized for Windows environments **RFC References** - Microsoft proprietary protocol (no formal RFC) - MS-RDP Protocol Documentation: https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/ **Use Cases** - Remote desktop access for Windows systems - IT support and remote administration with GUI - Remote working environments and virtual desktops **Alternative Protocols** - VNC – Cross-platform remote desktop sharing - TeamViewer, AnyDesk – Proprietary remote access solutions - SSH with X11 forwarding – GUI access on Unix/Linux .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: What You Will Learn in This Section **Let us learn more about RDP:** * :ref:`Learnings in this section ` * :ref:`Terminology ` * :ref:`Version Info ` * :ref:`RDP FAQs ` * :ref:`RDP Version&IEEE Details ` * :ref:`RDP Basic Setup on Ubuntu using IPv4 ` * :ref:`RDP Basic Setup on Ubuntu using IPv6 ` * :ref:`RDP Protocol Packet Details ` * :ref:`RDP Usecases ` * :ref:`RDP Basic Features ` * :ref:`Reference links ` .. button-link:: ./RDP.html :color: primary :shadow: :expand: Jump to "RDP" .. tab-set:: .. tab-item:: VNC (Virtual Network Computing) **Main Features** - Platform-independent remote desktop sharing over TCP ports starting at 5900 - Shares graphical desktops for remote control and support - Simple, lightweight, but typically unencrypted - Works across multiple operating systems **RFC References** - RFB (Remote Framebuffer) Protocol is the core VNC protocol - Specification available at RealVNC: https://www.realvnc.com/en/connect/docs/ **Use Cases** - Cross-platform remote technical support and desktop sharing - Remote access to Unix/Linux desktops and mixed environments - Training and collaborative screen sharing **Alternative Protocols** - RDP – Windows-focused remote desktop with advanced features - TeamViewer, AnyDesk – Enhanced secure remote desktop solutions - SSH with X11 forwarding – Unix/Linux GUI applications over secure channels .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: What You Will Learn in This Section **Let us learn more about VNC:** * :ref:`Learnings in this section ` * :ref:`Terminology ` * :ref:`Version Info ` * :ref:`VNC FAQs ` * :ref:`VNC Version&IEEE Details ` * :ref:`VNC Basic Setup on Ubuntu using IPv4 ` * :ref:`VNC Basic Setup on Ubuntu using IPv6 ` * :ref:`VNC Protocol Packet Details ` * :ref:`VNC Usecases ` * :ref:`VNC Basic Features ` * :ref:`Reference links ` .. button-link:: ./VNC.html :color: primary :shadow: :expand: Jump to "VNC"